Researchers at the University of Essex have developed a free mobile app that turns an iPhone or iPod into a hearing aid that could revolutionise the future for people with hearing loss. Unlike standard hearing aids that simply amplify all sounds, the BioAid app is inspired by biology and replicates the complexities of the human ear. It puts the user in control, is available to anyone, anywhere without the need for a hearing test, and potentially holds the key to a future where tiny, phone-based hearing aids can be dispensed and adjusted remotely.